Question

椭圆x²/(k+b)+y²/9的离心率e=c/a=1/2则k值为多少

Answer 1

e=c/a=1/2

c=1/2*a

c^2=a^2-b^2=1/4*a^2

3a^2=4b^2

3(k+6)=4*9

3k=18

k=6